For the most time, I've been firmly in the largest camp when it comes to the Mono debate - the 'I don't care'-camp. With patent lawsuits being hotter than Lady Gaga right now, that changed. For good reason, so it seems; while firmly in the 'ZOMG-MICROSOFT-IS-T3H-EVILL!1!!ONE!'-camp, The-Source.com investigated the five most popular Mono applications, and the conclusion is clear: all of them implement a lot of namespaces which are not covered by Microsoft's community promise thing.

Haskell, Erlang...
There are others, too.
If you require type checking, that kinda throws out CL, but there's Liskell if you want more flexibility of syntax than Haskell provides.
Everything starts obscure, so that's no argument in-and-of itself.

Both Haskell and Erlang actually have a relatively large number of useful libraries.

IDE? I'm not sure why one would want one, but some people _seem_ to want to program with a mouse...
I don't know anything about them, other than I... don't get it. Emacs user...

IDE? I'm not sure why one would want one, but some people _seem_ to want to program with a mouse...
I don't know anything about them, other than I... don't get it. Emacs user...

As an Emacs user, you should understand perfectly why someone would want an IDE - it practically *is* one.

As an Eclipse user, I almost never use the mouse, relying almost exclusively (and instinctively) on a huge number of shortcut keys for every conceivable operation. A single application for writing, compiling, running, debugging code? Tools for working with code - renaming, extracting functions, warning of possible errors? Plugins for everything else you could ever want?